Why do auto mechanics charge for diagnostics?

[roadman65]

As we all know when the ole Check Engine Light Comes on, you must go to a mechanic who has a computer that can communicate with your car's own computer. That act only requires a simple hook up that requires no hard labor. Yet the mechanic will charge 80 or so bucks.

What is the real reason for the cost?

[Life in Paradise]

As we all know when the ole Check Engine Light Comes on, you must go to a mechanic who has a computer that can communicate with your car's own computer. That act only requires a simple hook up that requires no hard labor. Yet the mechanic will charge 80 or so bucks.

What is the real reason for the cost?

There is a cost for having the diagnostic equipment and also the time for the tech to hook it up, and any training to read it properly.  Yes, the time may be minimal, and some shops will not charge you if they do the repair work.  They are in business to make a living, although one could argue this item could cost less than it does.

[roadman65]

As we all know when the ole Check Engine Light Comes on, you must go to a mechanic who has a computer that can communicate with your car's own computer. That act only requires a simple hook up that requires no hard labor. Yet the mechanic will charge 80 or so bucks.

What is the real reason for the cost?

There is a cost for having the diagnostic equipment and also the time for the tech to hook it up, and any training to read it properly.  Yes, the time may be minimal, and some shops will not charge you if they do the repair work.  They are in business to make a living, although one could argue this item could cost less than it does.

Sort of like the ambulance overcharging you to use their fleet when the cost comes from owning life saving equipment and services the same as an ER that has a standard market price.

[kphoger]

As we all know when the ole Check Engine Light Comes on, you must go to a mechanic who has a computer that can communicate with your car's own computer. That act only requires a simple hook up that requires no hard labor. Yet the mechanic will charge 80 or so bucks.

What is the real reason for the cost?

Does your mechanic only tell you the codes and then wish you luck figuring out what the problem is?  Or does your mechanic evaluate the codes, determine what is most likely causing them, and offer you a solution?

The first requires nothing but an OBD II scanner, and AutoZone does that free of charge.  The second requires knowledge and experience, and it puts the shop's reputation on the line.

[roadman65]

As we all know when the ole Check Engine Light Comes on, you must go to a mechanic who has a computer that can communicate with your car's own computer. That act only requires a simple hook up that requires no hard labor. Yet the mechanic will charge 80 or so bucks.

What is the real reason for the cost?

Does your mechanic only tell you the codes and then wish you luck figuring out what the problem is?  Or does your mechanic evaluate the codes, determine what is most likely causing them, and offer you a solution?

The first requires nothing but an OBD II scanner, and AutoZone does that free of charge.  The second requires knowledge and experience, and it puts the shop's reputation on the line.

Not disputing it at all. I knew there is a reason as all is never what it appears to be in life. Just curious what more there is than the hook up.

[Rothman]

As we all know when the ole Check Engine Light Comes on, you must go to a mechanic who has a computer that can communicate with your car's own computer. That act only requires a simple hook up that requires no hard labor. Yet the mechanic will charge 80 or so bucks.

What is the real reason for the cost?

What are you willing to do for me for free?

[J N Winkler]

As we all know when the ole Check Engine Light Comes on, you must go to a mechanic who has a computer that can communicate with your car's own computer. That act only requires a simple hook up that requires no hard labor. Yet the mechanic will charge 80 or so bucks.

What is the real reason for the cost?

I know for a fact that auto parts stores will do charging systems tests for free, though these typically do not include current measurements that can tell definitely whether the battery or alternator is close to failure.  I believe that they also do free readouts of generic DTCs with plug-in OBD II testers.

When a shop charges for diagnostic effort, there are several factors in play:

*  There is a time cost to pulling the car into the service bay and rolling it out when the customer decides not to proceed with the repair.  Once the car is in the bay, it also represents an opportunity cost since the space is unavailable for working on another car whose problems are known and whose owner has committed to a repair.

*  Often more specialized (and expensive) equipment is used to retrieve trouble codes specific to the make, and the charge contributes to amortization.

*  Sometimes troubleshooting goes beyond mere retrieval of trouble codes--e.g., using a fuel pressure tester to determine whether an OBD-II DTC associated with too-lean air/fuel mixture is due to a fuel pump on its way out and unable to maintain pressure consistently between 40 and 50 psi.

*  A standalone charge for diagnosis (especially if it is waived when the customer chooses to proceed with the suggested repair) discourages free-riding on the mechanic's time.

There are some non-critical problems I choose not to have repaired because past experience leads me to believe that the troubleshooting path a mechanic would have to follow would involve multiple transits in and out of a service bay, with a cost for each.  For example, I know the A/C in my daily driver has a slow leak (despite its receiving new valves and O-rings over the years) that, at this point, would involve a minimum of two shop visits to diagnose, and more probably at least four or five, because it loses refrigerant so slowly that it takes about a year before cooling action diminishes noticeably.  Moreover, the A/C never blew ice-cold even when it was brand-new and running to factory specification:  it was designed for both R-12 and R-134a but had the latter--which is associated with significantly worse cooling performance--as the initial charge.  Given that the car is 27 years old, titled as rebuilt salvage due to unrepaired hail damage, and has a scrap value of perhaps $400, I do not feel I would get a satisfactory return on the cost of having the A/C rendered fully leak-tight.

[hbelkins]

I can see a shop charging for a diagnostic scan if you choose not to have repair work done there, but most garages will still charge a flat-fee line item for the scan even if you have the repairs done. It's a quick way to make some money.

The solution, as mentioned by someone else, is to have an auto parts store that offers scanning services do the scan, you make a record of the code, and then go to a garage and say "this vehicle's check engine light is one, it's returning code XYZ123, fix whatever causes that code to throw." I'm certainly not a mechanic, but my understanding is that most (but not all) codes can be traced back to a specific part malfunctioning.

[roadman65]

I can see a shop charging for a diagnostic scan if you choose not to have repair work done there, but most garages will still charge a flat-fee line item for the scan even if you have the repairs done. It's a quick way to make some money.

The solution, as mentioned by someone else, is to have an auto parts store that offers scanning services do the scan, you make a record of the code, and then go to a garage and say "this vehicle's check engine light is one, it's returning code XYZ123, fix whatever causes that code to throw." I'm certainly not a mechanic, but my understanding is that most (but not all) codes can be traced back to a specific part malfunctioning.

Many will subtract the price of scan off the work to fix the issue.  That is why check your gas cap as that could prove costly if you forgot to replace it or tighten it.😁

[kphoger]

When a shop charges for diagnostic effort, there are several factors in play:

*  There is a time cost to pulling the car into the service bay and rolling it out when the customer decides not to proceed with the repair.  Once the car is in the bay, it also represents an opportunity cost since the space is unavailable for working on another car whose problems are known and whose owner has committed to a repair.

*  Often more specialized (and expensive) equipment is used to retrieve trouble codes specific to the make, and the charge contributes to amortization.

*  Sometimes troubleshooting goes beyond mere retrieval of trouble codes--e.g., using a fuel pressure tester to determine whether an OBD-II DTC associated with too-lean air/fuel mixture is due to a fuel pump on its way out and unable to maintain pressure consistently between 40 and 50 psi.

Mechanics also might need to spend time hunting down flowcharts for your particular vehicle and follow the paths outlined therein, as part of the elimination process.

I'm certainly not a mechanic, but my understanding is that most (but not all) codes can be traced back to a specific part malfunctioning.

They can usually be traced back to the most likely specific part.  However, there are usually other parts that might throw the same code.



The best solution is to know someone who's a mechanic, get on their friends and family discount program, and receive diagnoses free of charge.

[formulanone]

As we all know when the ole Check Engine Light Comes on, you must go to a mechanic who has a computer that can communicate with your car's own computer. That act only requires a simple hook up that requires no hard labor.

1) If it's not "hard labor", why aren't you doing it yourself? Anything that you do not wish to do means: I cannot or will not perform it.

(Exceptions for an applicable warranty or recall.)

2) Your plumber and A/C technician probably also charge some sort of fee for arriving at your house. If not directly, they've probably packed it into the price, or you have some sort of pre-arrangement for service.

3) The code reader is not the end-all and be-all of the repair. Not all failures will trigger a warning light or failure code!
a. One failed component can disguise other failed components.
b. One improper repair, ignored repair, or failed item can mask other repairs.
c. Vehicles are weird: sometimes multiple failure codes do not equal the same number of repairs or even the precise type of repair.

4) Yes, your mechanic suggested that it's probably an O₂ / air-fuel / lambda sensor. Why didn't the mechanic perform the repair?
a. It's a PITA to replace it.
b. Doesn't have the specialized equipment or tool for it.
c. Is guessing/speculating because your vehicle merely came up in conversation.
d. Doesn't want to deal with you/your vehicle.
e. Already dealing with too many other PITAs, or would rather enjoy eating an actual pita.

5) Your vehicle may have been hastily modified, adulterated, improperly repaired, used incorrect/bad parts, victim of bad advice, struck by lightning, became a rodent domicile, encountered a jealous lover, struck by another vehicle, overloaded, is used in excessive weather conditions, came in contact with an object in the road, contains a loose nut behind the wheel, suffered from rapidly deaccelerating interior cargo, had an unwitting family member pour washer fluid in the brake reservoir, been struck with a half-dozen high heel shoes, just has a lot of time and/or miles of normal use, had been the subject of an exorcism and/or appeared in The Exorcism.

Your mechanic, shop foreman, and service advisor knows none of this ahead of time, and if you knew any of this happened ahead of time, you'd never tell them at the time of the initial service write-up. The reassuring thing is that this makes you like 95% of most folks.

6) Diagnosing it on social media is akin to reading and digesting all of the "comments" in a news article. 2% of the time, it's painfully but spot-on correct, but the other 98% is just idle guesswork since they're not professionals either. The question remains...do you put your faith and finances in 1:50 odds? See step (1) if it's actually easy enough and doesn't cause injury, fire, nor gets you in trouble with your homeowner's association.

Yet the mechanic will charge 80 or so bucks.
What is the real reason for the cost?

Overhead costs and opportunity costs; $80 is on the lower side of things, being that the average price of dealership labor is about $110-120/hour.

<source, this is my racket>

[Max Rockatansky]

Basically a lot of shops charge an hour of labor to do "anything"  even if it takes just a couple seconds. 

[kphoger]

Basically a lot of shops charge an hour of labor to do "anything"  even if it takes just a couple seconds. 

Which is especially understandable considering that, if they estimate your job to take eight hours of labor and it ends up taking twenty hours because your vehicle was designed by people whose primary concern was not ease of access, you still only pay for the eight hours quoted.

[Max Rockatansky]

Basically a lot of shops charge an hour of labor to do "anything"  even if it takes just a couple seconds. 

Which is especially understandable considering that, if they estimate your job to take eight hours of labor and it ends up taking twenty hours because your vehicle was designed by people whose primary concern was not ease of access, you still only pay for the eight hours quoted.

When I worked in a shop in high school at the garage I worked at we charged $50 for a code diagnostic which is what our labor rate per hour was.  Someone still had to talk to the customer, run the code and explain to them what it meant.  Usually said process would take 20-40 minutes depending on how busy we were.  It was completely reasonable in my view to charge for something like that given there is still an employee running around having to do work.   

[J N Winkler]

I don't actually have an OBD II code reader.  Why not?  The main reason is that the vehicles in the family fleet that have OBD II have not set a CEL even once in a combined 28 years of service.

Meanwhile, the one car that still has OBD I actually has an issue that needs to be resolved, but is not setting a CEL, so that is not available for diagnosis.  When it warms up, it hesitates lightly when it is cruising at a steady speed between 1500 and 2000 RPM (about 35 to 45 MPH in top gear).  The range of possible causes is broad--bad spark plugs, bad ignition coil, bad EGR, fuel pump on its way out, etc.  (I suspect the latter simply because it involves the most trouble.)

Whether the shop charges for DTC retrieval is often only a small part of the big picture.

[US71]

I've been using the same mechanic for close to 10 years. They rarely charge me just to look, but they also know I come to them first. I will NOT use the "Evil Empire" as they either fix the wrong thing or fix the right thing cheaply.

[jeffandnicole]

Places charge because of this:

"Oh, it's just that?  OK, my buddy can fix it."

"Oh, it's just that?  I'll go get the part at Walmart/Autozone/Amazon."

"Oh, it's just that?  Well, why can't you just fix it right now?"

Places have been burned way too often trying to offer a free service.  And if for some reason it wasn't diagnosed correctly, the customer will come complaining to them...even though they never even paid for the service to begin with.  The person could've gone to their buddy...but didn't trust them enough.  So they went to a place they trust, wanting free advise.

Basically a lot of shops charge an hour of labor to do "anything"  even if it takes just a couple seconds. 

Lots of things take just a little time...as long as you don't include the rest of the time involved.

If it only took them a few seconds to fix the car, then that means they are well trained, and someone monitored the inventory to make sure they had common parts on hand.

Of course, if it was that easy, you should've just fixed it yourself.  Don't forget to include the multiple minutes of multiple Youtube watching to figure out what part you need, and the drive to and from the store to get the part, along with the many minutes of figuring out what your doing, with the tool that probably isn't the right tool but it's what you had laying around the house.

[texaskdog]

Free at Autozone

[zachary_amaryllis]

As we all know when the ole Check Engine Light Comes on, you must go to a mechanic who has a computer that can communicate with your car's own computer. That act only requires a simple hook up that requires no hard labor. Yet the mechanic will charge 80 or so bucks.

What is the real reason for the cost?

i went to jiffy lube the other day, and they read it at no additional cost, and told me exactly what the problem was. oxygen sensor.

[Roadgeekteen]

Capitalism

[SP Cook]

- As stated, any of the chain stores will read the codes for you for free. 

- Said same chain stores will sell you a simple layman's scan tool WITH AN ERASE BUTTON for about $80.

My method is to read the code, and then erase them.  If they come back, then something is wrong.  If not then its fine.  For example, I once left my lights on.  Caused four codes about electrical. I knew I just left the lights on, got a jump, cleared the codes and drove the car for 6 years with no problems. 

If the codes come back, then something really is wrong.  Go to YouTube and just search for the code and your make.  You will find videos that will tell you what parts could be causing the code, how to replace or repair, how serious it really is, and the basic difficulty (which can range from "you screw in a new $3 whatever" to "you probably need a mechanic" to "fill the crankcase full of Casite and sell the car to some sucker".

[hbelkins]

A mechanic I used to use didn't keep track of time. He just referred to some industry-standard labor guide book for the work performed and charged that number of hours.

For instance, if the book said "replace gonkulator* 1.5" then he wrote down 1.5 hours on the service ticket and that's the price you paid. Didn't matter if the actual replacement took 45 minutes or three hours. My experience was most always that the actual labor time was less than the book estimate. That's one reason he is now my ex-mechanic.

*"Gonkulator" was a fake part often mentioned in rec.autos.sport.nascar back in Usenet's heyday. It was frequently mentioned as a part that broke that knocked some driver out of the race, or as one that could be illegally modified to produce more speed or horsepower. We actually got Mike Joy, who lurked and sometimes posted in RASN, to mention it once in a television broadcast.

[kphoger]

A mechanic I used to use didn't keep track of time. He just referred to some industry-standard labor guide book for the work performed and charged that number of hours.

For instance, if the book said "replace gonkulator* 1.5" then he wrote down 1.5 hours on the service ticket and that's the price you paid. Didn't matter if the actual replacement took 45 minutes or three hours. My experience was most always that the actual labor time was less than the book estimate. That's one reason he is now my ex-mechanic.

*"Gonkulator" was a fake part often mentioned in rec.autos.sport.nascar back in Usenet's heyday. It was frequently mentioned as a part that broke that knocked some driver out of the race, or as one that could be illegally modified to produce more speed or horsepower. We actually got Mike Joy, who lurked and sometimes posted in RASN, to mention it once in a television broadcast.

That's what my mechanic does.  That really helped me last year, when a 10.5-hour job ended up taking several weeks.

[GCrites]

In general any business that is "nice" can't be like that for long. If they are, very soon they will have a bunch of new "best friends" that can quickly bring it to its knees. That's why businesses should be "courteous" and "helpful" but not "nice". Free full diagnosis is "nice". An AutoZoner plugging in a standard code reader that sells for $50-$200 and reading off the codes so that you can write them down is "helpful". As stated above, reading codes is only the second step in a diagnosis with the first being a visual/auditory/olfactory inspection.

[texaskdog]

Even the dealer wanted to charge me $90 for one.  If they do the repairs there they should waive the fee I would think.